The comfort of use and the visibility of a screen display, but also the appearance of a screen when it is switched off depend mostly on the prevailing lighting conditions. Reflections of ambient light on the surface of the screen are annoying for a viewer. This is the case especially with so-called glare, that is to say reflections of intensive local incident light, in the direction of the viewer. However, diffuse scattering of ambient light on the surface of a screen generally also has an adverse effect on the visibility and the aesthetic appearance of the screen display and of the screen.
When using portable display devices, such as, for example, notebooks or mobile telephones, and devices within the home, it is often easy for the user to influence the ambient lighting conditions or to suppress particularly annoying reflections by turning the device slightly. However, these possibilities exist to only a very limited extent in the case of fixed or removable displays installed in motor vehicles, such as, for example, navigation instruments or tablet PCs. While frequent changes of the surroundings or of the position of the vehicle can lead to a constant change in the ambient lighting conditions, it is at the same time often not possible, and generally also not desirable, for the driver or passenger to adjust the screen correspondingly frequently to the prevailing lighting conditions, for example by changing the orientation of the installed devices.
Possibilities for reducing annoying reflections on screen surfaces have already been known for a relatively long time. They include anti-reflection coatings as well as measures for avoiding glare, such as, for example, special anti-glare coatings or a roughening of the surface, as a result of which incident light is not reflected but is scattered diffusely.
In the forms known hitherto, roughened screen surfaces often appear greyish when the display is switched off owing to the passive scattering of ambient light, and this is perceived as unattractive by many users. At the same time, anti-glare and anti-reflection coatings can be used to only a limited extent for touch-sensitive screens, as are common in tablet PCs and automotive instruments, because of their sensitivity to fingerprints and their poor scratch resistance.